Complex compounds and their use in olefin polymerization

ABSTRACT

Complexes of the formulae I a to d,  
                 
 
     where M is an element of groups 6 to 10 of the Periodic Table of the Elements, preferably Ni, can be used for the polymerization and copolymerization of olefins, for example in suspension polymerization processes, gas-phase polymerization processes, bulk polymerization processes and emulsion polymerization processes.

[0001] The present invention relates to complexes of the formulae I a tod,

[0002] where the variables are defined as follows:

[0003] M is an element of groups 6 to 10 of the Periodic Table of theElements in the oxidation state +2 to +4,

[0004] Nu is selected from among O, S and N—R⁷;

[0005] R¹ to R⁷ are selected from among

[0006] hydrogen,

[0007] C₁-C₈-alkyl, substituted or unsubstituted,

[0008] C₂-C₈-alkenyl, substituted or unsubstituted, having from one to 4isolated or conjugated double bonds;

[0009] C₃-C₁₂-cycloalkyl, substituted or unsubstituted, C₇-C₁₃-aralkyl,

[0010] C₆-C₁₄-aryl, unsubstituted or substituted by one or moreidentical or different substituents selected from among

[0011] C_(l)-C₈-alkyl, substituted or unsubstituted,

[0012] C₃-C₁₂-cycloalkyl,

[0013] C₇-C₁₃-aralkyl,

[0014] C₆-C₁₄-aryl,

[0015] halogen,

[0016] C₁-C₆-alkoxy, substituted or unsubstituted,

[0017] C₆-C₁₄-aryloxy,

[0018] SiR⁸R⁹R¹⁰ and O—SiR⁸R⁹R¹⁰;

[0019] five- and six-membered nitrogen-containing heteroaryl radicals,unsubstituted or substituted by one or more identical or differentsubstituents selected from among

[0020] C₁-C₈-alkyl, substituted or unsubstituted,

[0021] C₃-C₁₂-cycloalkyl,

[0022] C₇-C₁₃-aralkyl,

[0023] C₆-C₁₄-aryl,

[0024] halogen,

[0025] C₁-C₆-alkoxy,

[0026] C₆-C₁₄-aryloxy,

[0027] SiR⁸R⁹R¹⁰ and O—SiR⁸R⁹R¹⁰;

[0028] where adjacent radicals R¹ to R⁷ may be joined to one another toform a 5- to 12-membered ring;

[0029] L¹ is an uncharged, organic or inorganic ligand,

[0030] L² is an organic or inorganic anionic ligand, where L¹ and L² maybe joined to one another by one or more covalent bonds,

[0031] z is an integer from 1 to 3,

[0032] R⁸ to R¹⁰ are identical or different and are selected from amonghydrogen, C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl andC₆-C₁₄-aryl.

[0033] The present invention also relates to a process for preparing thenovel complexes from ligands of the formula II,

[0034] and a process for the polymerization or copolymerization ofolefins using a complex of the formula I.

[0035] Furthermore, the present invention relates to a process forpreparing supported polymerization catalysts using the novel complex ofthe formula I, and to a process for the polymerization orcopolymerization of olefins using the novel supported catalysts.

[0036] Finally, the present invention relates to a process for theemulsion polymerization and copolymerization of olefins using a complexhaving one of the formulae I a to I d.

[0037] Polymers and copolymers of olefins are of great economicimportance because the monomers are readily available in largequantities and because the polymers can be varied within a wide range byvariation of the method of preparation or the processing parameters. Thecatalyst used is of particular significance in the process for preparingthe polymers. Apart from Ziegler-Natta catalysts, various single-sitecatalysts are of increasing importance. In the latter, central atomswhich have been examined in some detail include not only Zr as in, forexample, metallocene catalysts (H.-H. Brintzinger et al., Angew. Chem.1995, 107, 1255) but also Ni or Pd (WO 96/23010) or Fe and Co (e.g. WO98/27124). The complexes of Ni, Pd, Fe and Co are also referred to ascomplexes of late transition metals.

[0038] Metallocene catalysts have disadvantages for industrial use. Themost frequently employed metallocenes, namely zirconocenes andhafnocenes, are sensitive to hydrolysis. In addition, most metallocenesare sensitive to many catalyst poisons such as alcohols, ethers and CO,which makes it necessary for the monomers to be carefully purified.

[0039] While Ni and Pd complexes (WO 96/23010) catalyze the formation ofhighly branched polymers which are of little commercial interest, theuse of Fe or Co complexes leads to formation of highly linearpolyethylene containing very low proportions of comonomer.

[0040] Furthermore, complexes by means of which ethylene can bepolymerized or copolymerized in the presence of water have been studied.

[0041] WO 98/42664 describes complexes of the formula A and closelyrelated derivatives containing salicylaldimine ligands and also theiruse for the polymerization of olefins.

[0042] WO 98/42665 describes complexes of the formula B and closelyrelated derivatives and also their use for the polymerization ofolefins. In the complexes of both the formula A and the formula B, theradical R on the imine nitrogen is a C₁-C₁₁-alkyl group or anortho-substituted phenyl group. However, their activity should becapable of improvement.

[0043] It is also known that the complexes of the formulae A and B arepolymerization-active even in the presence of small amounts of water,without the catalytic activity being adversely affected (Wo 98/42664, inparticular page 17, line 14 ff; WO 98/42665, p. 16, line 13). However,these amounts of water must not exceed 100 equivalents, based on thecomplex (WO 98/42664, page 17, lines 33-35; WO 98/42665, page 16, lines30-31). However, an emulsion polymerization cannot be carried out underthese conditions. In Macromol. Symp. 2000, 150, 53, A. Tomov et al.reported that some binuclear Ni complexes are suitable as catalysts foremulsion polymerization of ethylene. However, the synthesis of thecomplexes mentioned is complicated.

[0044] Wo 98/30609 discloses derivatives of A which are suitable for thepolymerization of ethylene and propylene. However, their activity is notalways satisfactory.

[0045] EP-A 0 874 005 discloses further polymerization-active complexes.These are preferably Ti complexes with salicylaldimine ligands. Thesetoo bear phenyl substituents or substituted phenyl substituents on thealdimine nitrogen (pages 18-23) or else the aldimine nitrogen isincorporated into a 6-membered ring (pages 31-32). However, they arevery sensitive to polar compounds such as water, alcohols or ethers.

[0046] In DE-A 199 61 340 it is shown that complexes of late transitionmetals having the formulae C and D

[0047] where R to R″″′ are each hydrogen, alkyl, C₇-C₁₃-aralkyl orC₆-C₁₄-aryl, and mixtures thereof are suitable for polymerizing ethyleneby emulsion polymerization. However, the activities should be capable ofimprovement. In A. Held et al., J. Chem. Soc., Chem. Commun. 2000, 301,it is shown that complexes of the formula C in which R is phenyl and R″is an SO₃—group will polymerize ethylene in an aqueous medium. Theactivity of C, too, is not yet optimal.

[0048] Owing to the great commercial importance of polyolefins, thesearch for very versatile polymerization-active complexes having thehighest possible activity continues to be of great importance.

[0049] It is an object of the present invention,

[0050] to provide new complexes which are suitable for thepolymerization of olefins;

[0051] to provide a process for preparing the complexes of the presentinvention;

[0052] to provide a process for the polymerization or copolymerizationof olefins using the complexes of the present invention;

[0053] to provide supported catalysts for the polymerization of olefinsand a process for preparing the supported catalysts of the presentinvention using the complexes of the present invention;

[0054] to polymerize and copolymerize olefins using the supportedcatalysts of the present invention;

[0055] to provide a process for the emulsion polymerization orcopolymerization of olefins, in particular ethylene, using the complexesof the present invention.

[0056] We have found that this object is achieved by means of complexeshaving the structures of the formulae I a to d defined at the outset.

[0057] In the formulae I a to d, the variables are defined as follows: Mis an element of groups 6 to 10 of the Periodic Table of the Elements inthe oxidation state from +2 to +4; preferably Cr, Fe, Pd or Ni,particularly preferably Ni.

[0058] Nu is selected from among O, S and N—R⁷, with oxygen beingpreferred;

[0059] R¹ to R⁷ are identical or different and are selected from among

[0060] hydrogen,

[0061] C₁-C₁₈-alkyl groups, such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,sec-hexyl, n-heptyl, isoheptyl n-octyl, n-decyl, n-dodecyl andn-octadecyl; preferably C₁-C₁₂-alkyl such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl,isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,isohexyl, sec-hexyl and n-decyl, particularly preferably C₁-C₄-alkylsuch as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyland tert-butyl;

[0062] examples of substituted C₁-C₁₈-alkyl groups are:

[0063] monohalogenated or polyhalogenated C₁-C₈-alkyl groups such asfluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl,dichloromethyl, trichloromethyl, bromomethyl, dibromomethyl,tribromomethyl, pentafluoroethyl, perfluoropropyl and perfluorobutyl,particularly preferably fluoromethyl, difluoromethyl, trifluoromethyland perfluorobutyl;

[0064] C₂-C₁₈-alkenyl having from one to 4 isolated or conjugated doublebonds, for example vinyl, 1-allyl, 3-allyl, ω-butenyl, ω-pentenyl,ω-hexenyl, 1-cis-buta-1,3-dienyl and 1-cis-hexa-1,5-dienyl.

[0065] examples of substituted C₂-C₁₈-alkenyl groups are:

[0066] isopropenyl, 1-isoprenyl, α-styryl, β-styryl,1-cis-1,2-phenylethenyl and 1-trans-1,2-phenylethenyl.

[0067] C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,cycloundecyl and cyclododecyl; preferably cyclopentyl, cyclohexyl andcycloheptyl;

[0068] examples of substituted cycloalkyl groups are:

[0069] 2-methylcyclopentyl, 3-methylcyclopentyl,cis-2,4-dimethylcyclopentyl, trans-2,4-dimethylcyclopentyl,cis-2,5-dimethylcyclopentyl, trans-2,5-dimethylcyclopentyl,2,2,5,5-tetramethylcyclopentyl, 2-methylcyclohexyl, 3-methylcyclohexyl,4-methylcyclohexyl, cis-2,6-dimethylcyclohexyl,trans-2,6-dimethylcyclohexyl, cis-2,6-diisopropylcyclohexyl,trans-2,6-diisopropylcyclohexyl, 2,2,6,6-tetramethylcyclohexyl,2-methoxycyclopentyl, 2-methoxycyclohexyl, 3-methoxycyclopentyl,3-methoxycyclohexyl, 2-chlorocyclopentyl, 3-chlorocyclopentyl,2,4-dichlorocyclopentyl, 2,2,4,4-tetrachlorocyclopentyl,2-chlorocyclohexyl, 3-chlorocyclohexyl, 4-chlorocyclohexyl,2,5-dichlorocyclohexyl, 2,2,6,6-tetrachlorocyclohexyl,2-thiomethylcyclopentyl, 2-thiomethylcyclohexyl,3-thiomethylcyclopentyl, 3-thiomethylcyclohexyl and further derivatives;

[0070] C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly preferablybenzyl;

[0071] C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably phenyl,1-naphthyl and 2-naphthyl, particularly preferably phenyl;

[0072] C₆-C₁₄-aryl such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl,2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl,4-phenanthryl and 9-phenanthryl substituted by one or more identical ordifferent substituents selected from among

[0073] C₁-C₁₈-alkyl groups such as methyl, ethyl, n-propyl, isopropyl,h-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,sec-hexyl, n-heptyl, isoheptyl n-octyl, n-decyl, n-dodecyl andn-octadecyl, preferably C₁-C₁₂-alkyl such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl,isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,isohexyl, sec-hexyl and n-decyl, particularly preferably C_(l)-C₄-alkylsuch as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyland tert-butyl;

[0074] examples of substituted C₁-C₁₈-alkyl groups are:

[0075] monohalogenated or polyhalogenated C₁-C₈-alkyl groups such asfluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl,dichloromethyl, trichloromethyl, bromomethyl, dibromomethyl,tribromomethyl, pentafluoroethyl, perfluoropropyl and perfluorobutyl,particularly preferably fluoromethyl, difluoromethyl, trifluoromethyland perfluorobutyl;

[0076] C₂-C₁₈-alkenyl having from one to 4 isolated or conjugated doublebonds, for example vinyl, 1-allyl, 3-allyl, ω-butenyl, ω-pentenyl,ω-hexenyl, 1-cis-buta-1,3-dienyl and 1-cis-hexa-1,5-dienyl.

[0077] examples of substituted C₂-C8-alkenyl groups are:

[0078] isopropenyl, 1-isoprenyl, α-styryl, β-styryl,1-cis-1,2-phenylethenyl and 1-trans-1,2-phenylethenyl.

[0079] C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,cycloundecyl and cyclododecyl; preferably cyclopentyl, cyclohexyl andcycloheptyl;

[0080] C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly preferablybenzyl;

[0081] C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably phenyl,1-naphthyl and 2-naphthyl, particularly preferably phenyl;

[0082] halogen, for example fluorine, chlorine, bromine and iodine,particularly preferably fluorine and chlorine;

[0083] C₁-C₆-alkoxy groups such as methoxy, ethoxy, n-propoxy,isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy,isopentoxy, n-hexoxy and isohexoxy, particularly preferably methoxy,ethoxy, n-propoxy and n-butoxy;

[0084] C₆-C₁₄-aryloxy groups such as phenoxy, ortho-cresyloxy,meta-cresyloxy, para-cresyloxy, α-naphthoxy, β-naphthoxy and9-anthryloxy;

[0085] silyl groups SiR⁸R⁹R¹⁰, where R⁸ to R¹⁰ are selectedindependently from among hydrogen, C₁-C₈-alkyl groups, benzyl radicalsand C₆-C₁₄-aryl groups; with preference being given to thetrimethylsilyl, triethylsilyl, triisopropylsilyl, diethylisopropylsilyl,dimethylhexylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl,tribenzylsilyl, triphenylsilyl and tri-para-xylylsilyl groups andparticular preference being given to the trimethylsilyl group and thetert-butyldimethylsilyl group;

[0086] silyloxy groups OSiR⁸R⁹R¹⁰, where R⁸ to R¹⁰ are selectedindependently from among hydrogen, C₁-C₈-alkyl groups, benzyl radicalsand C₆-C₁₄-aryl groups; with preference being given to thetrimethylsilyloxy, triethylsilyloxy, triisopropylsilyloxy,diethylisopropylsilyloxy, dimethylthexylsilyloxy,tert-butyldimethylsilyloxy, tert-butyldiphenylsilyloxy,tribenzylsilyloxy, triphenylsilyloxy and tri-para-xylylsilyloxy groupsand particular preference being given to the trimethylsilyloxy group andthe tert-butyldimethylsilyloxy group;

[0087] five and six-membered nitrogen-containing heteroaryl radicalssuch as N-pyrrolyl, pyrrol-2-yl, pyrrol-3-yl, N-imidazolyl,2-imidazolyl, 4-imidazolyl, 1,2,4-triazol-3-yl, 1,2,4-triazol-4-yl,2-pyridyl, 3-pyridyl, 4-pyridyl, 3-pyridazinyl, 4-pyridazinyl,2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, N-indolyl and N-carbazolyl;

[0088] five- and six-membered nitrogen-containing heteroaryl radicalssuch as N-pyrrolyl, pyrrol-2-yl, pyrrol-3-yl, N-imidazolyl,2-imidazolyl, 4-imidazolyl, 1,2,4-triazol-3-yl, 1,2,4-triazol-4-yl,2-pyridyl, 3-pyridyl, 4-pyridyl, 3-pyridazinyl, 4-pyridazinyl,2-pyrimidinyl, 4-pyrimidinyl, 5-pyrimidinyl, N-indolyl and N-carbazolylsubstituted by one or more identical or different substituents selectedfrom among

[0089] C₁-C₁₈-alkyl groups such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,sec-hexyl, n-heptyl, isoheptyl n-octyl, n-decyl, n-dodecyl andn-octadecyl, preferably C_(l)-C₁₂-alkyl such as methyl, ethyl, n-propyl,isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl,isopentyl, sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl,isohexyl, sec-hexyl and n-decyl, particularly preferably C_(l)-C₄-alkylsuch as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyland tert-butyl;

[0090] examples of substituted C_(l)-C₁₈-alkyl groups are:

[0091] monohalogenated or polyhalogenated C₁-C₈-alkyl groups such asfluoromethyl, difluoromethyl, trifluoromethyl, chloromethyl,dichloromethyl, trichloromethyl, bromomethyl, dibromomethyl,tribromomethyl, pentafluoroethyl, perfluoropropyl and perfluorobutyl,particularly preferably fluoromethyl, difluoromethyl, trifluoromethyland perfluorobutyl;

[0092] C₂-C₁₈-alkenyl having from one to 4 isolated or conjugated doublebonds, for example vinyl, 1-allyl, 3-allyl, ω-butenyl, ω-pentenyl,ω-hexenyl, 1-cis-buta-1,3-dienyl and 1-cis-hexa-1,5-dienyl.

[0093] examples of substituted C₂-C₈-alkenyl groups are:

[0094] isopropenyl, 1-isoprenyl, α-styryl, β-styryl,1-cis-1,2-phenylethenyl and 1-trans-1,2-phenylethenyl.

[0095] C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,cycloundecyl and cyclododecyl; preferably cyclopentyl, cyclohexyl andcycloheptyl;

[0096] C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly preferablybenzyl;

[0097] C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably phenyl,1-naphthyl and 2-naphthyl, particularly preferably phenyl;

[0098] halogen, for example fluorine, chlorine, bromine and iodine,particularly preferably fluorine and chlorine;

[0099] C_(l)-C₆-alkoxy groups such as methoxy, ethoxy, n-propoxy,isopropoxy, n-butoxy, isobutoxy, sec-butoxy, tert-butoxy, n-pentoxy,isopentoxy, n-hexoxy and isohexoxy, particularly preferably methoxy,ethoxy, n-propoxy and n-butoxy;

[0100] C₆-C₁₄-aryloxy groups such as phenoxy, ortho-cresyloxy,meta-cresyloxy, para-cresyloxy, α-naphthoxy, β-naphthoxy and9-anthryloxy;

[0101] silyl groups SiR⁸R⁹R¹⁰, where R⁸ to R¹⁰ are selectedindependently from among hydrogen, C₁-C₈-alkyl groups, benzyl radicalsand C₆-C₁₄-aryl groups; with preference being given to thetrimethylsilyl, triethylsilyl, triisopropylsilyl, diethylisopropylsilyl,dimethylhexylsilyl, tert-butyldimethylsilyl, tert-butyldiphenylsilyl,tribenzylsilyl, triphenylsilyl and tri-para-xylylsilyl groups andparticular preference being given to the trimethylsilyl group and thetert-butyldimethylsilyl group;

[0102] silyloxy groups OSiR⁸R⁹R¹⁰, where R⁸ to R¹⁰ are selectedindependently from among hydrogen, C₁-C₈-alkyl groups, benzyl radicalsand C₆-C₁₄-aryl groups; with preference being given to thetrimethylsilyloxy, triethylsilyloxy, triisopropylsilyloxy,diethylisopropylsilyloxy, dimethylthexylsilyloxy,tert-butyldimethylsilyloxy, tert-butyldiphenylsilyloxy,tribenzylsilyloxy, triphenylsilyloxy and tri-para-xylylsilyloxy groupsand particular preference being given to the trimethylsilyloxy group andthe tert-butyldimethylsilyloxy group.

[0103] In a particular embodiment, adjacent radicals R¹ to R⁷ may bejoined to one another to form a 5- to 12-membered ring. For example, R¹and R⁶ may together be: —(CH₂)₃- (trimethylene), —(CH₂)₄-(tetramethylene), —(CH₂)₅- (pentamethylene), —(CH₂)₆-(hexamethylene),—CH₂—CH═CH—, —CH₂—CH═CH—CH₂—, —CH═CH—CH═CH—, —O—CH₂—O—, —O—CHMe—O—,—O—CH—(C₆H₅)—O—, —O—CH₂—CH₂—0—, —O—CMe₂—0—, —NMe—CH₂—CH₂—NMe—,—NMe—CH₂—NMe— or —O—SiMe₂—O— where Me═CH₃. In a preferred example, R¹and R⁶ together form a 1,3-butadiene-1,4-diyl unit which may in turn bemonosubstituted or polysubstituted by C₁-C₈-alkyl. In a furtherpreferred example R² and R⁴ together form a 1,3-butadien-1,4-diyl unitwhich may in turn be monosubstituted or polysubstituted by C₁-C₈-alkyl.

[0104] L¹ is selected from among uncharged, inorganic and organicligands, for example phosphines of the formula (R¹¹)_(x)PH_(3−x) oramines of the formula (R¹¹)_(x)NH_(3−x), where x is an integer from 0 to3. However, ethers (R¹¹)₂O such as dialkyl ethers, e.g. diethyl ethers,or cyclic ethers, e.g. tetrahydrofuran, H₂O, alcohols (R¹¹)OH such asmethanol or ethanol, pyridine, pyridine derivatives of the formulaC₅H_(5−x)(R¹³)_(x)N, for example 2-picoline, 3-picoline, 4-picoline,2,3-lutidine, 2,4-lutidine, 2,5-lutidine, 2,6-lutidine or 3,5-lutidine,CO, C₁-C₁₂-alkylnitriles or C₆-C₁₄-arylnitriles, e.g. acetonitrile,propionitrile, butyronitrile or benzonitrile, are also suitable. It isalso possible to use singly or multiply ethylenically unsaturated doublebond systems such as ethenyl, propenyl, cis-2-butenyl, trans-2-butenyl,cyclohexenyl or norbornenyl as ligand.

[0105] L² is selected from among inorganic and organic anionic ligands,for example from among

[0106] halide ions such as fluoride, chloride, bromide and iodide,preferably chloride and bromide,

[0107] amide anions (R¹¹)_(x−1)NH_(2−x), where x is an integer from 0 to3,

[0108] C₁-C₆-alkyl anions such as (CH₃)⁻, (C₂H₅)⁻, (C₃H₇)⁻, (n-C₄H₉)⁻,(tert-C₄H₉)⁻and (C₆H₁₄)⁻;

[0109] allyl anions and methallyl anions,

[0110] benzyl anions and

[0111] aryl anions such as (C₆H₅)⁻.

[0112] z is an integer from 1 to 3, e.g. 0, 1, 2 or 3;

[0113] R¹ are identical or different and are selected from among

[0114] hydrogen,

[0115] C₁-C₈-alkyl groups,

[0116] benzyl radicals and

[0117] C₆-C₁₄-aryl groups, where these groups are as defined above andwhere 2 radicals R¹¹ may be covalently bound to one another.

[0118] In a particular embodiment, L¹ and L² are joined to one anotherby one or more covalent bonds. Examples for such ligands are1,5-cyclooctadienyl ligands (“COD”), 1,6-cyclodecenyl ligands and1,5,9-all-trans-cyclododecatrienyl ligands.

[0119] In a further particular embodiment, L¹ istetramethylethylenediamine, with only one nitrogen coordinating to thenickel.

[0120] The novel complexes of the formulae I a to d are generallyprepared from ligands of the formula II a or II b, in which thevariables are as defined above. To synthesize the complexes of thepresent invention, the ligands are firstly deprotonated by means of abase and subsequently reacted with metal compounds of the formula MX₂,MX₃, MX₄ or ML¹L².

[0121] Bases which can be used are the metal alkyls customary inorganometallic chemistry, for example methyllithium, ethyllithium,n-butyllithium, sec-butyllithium, tert-butyllithium or hexyllithium,also Grignard compounds such as ethylmagnesium bromide, also lithiumamide, sodium amide, potassium amide, potassium hydride or lithiumdiisopropylamide (“LDA”). Solvents which have been found to be usefulare high-boiling solvents such as toluene, ortho-xylene, meta-xylene,para-xylene, ethylbenzene or mixtures of these, also acyclic or cyclicethers such as 1,2-dimethoxyethane, tetrahydrofuran or diethyl ether.

[0122] This deprotonation is generally complete after a few hours; it isappropriate to employ a reaction time of from 2 to 10 hours, preferablyfrom 3 to 5 hours. The temperature conditions are generally notcritical; temperatures of from −90° C. to −20° C. are preferred for thedeprotonation.

[0123] The deprotonated ligand and the metal compound of the formulaMX₂, MX₃, MX₄ or ML¹L² are subsequently reacted with one another.

[0124] X are identical or different and are selected from among: halogensuch as fluorine, chlorine, bromine and iodine, preferably chlorine andbromine;

[0125] C_(l)-C₈-alkyl groups such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl,sec-pentyl, neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl,sec-hexyl, n-heptyl, isoheptyl and n-octyl; preferably C₁-C₆-alkyl suchas methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl,tert-butyl, n-pentyl, isopentyl, sec-pentyl, neopentyl,1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl, particularlypreferably C₁-C₄-alkyl such as methyl, ethyl, n-propyl, isopropyl,n-butyl, isobutyl, sec-butyl and tert-butyl;

[0126] C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,cycloundecyl and cyclododecyl; preferably cyclopentyl, cyclohexyl andcycloheptyl;

[0127] C₇-C₁₃-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,3-phenylpropyl, neophyl (1-methyl-1-phenylethyl), 1-phenylbutyl,2-phenylbutyl, 3-phenylbutyl and 4-phenylbutyl, particularly preferablybenzyl;

[0128] C₆-C₁₄-aryl, for example phenyl, 1-naphthyl, 2-naphthyl,1-anthryl, 2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl,3-phenanthryl, 4-phenanthryl and 9-phenanthryl, preferably phenyl,1-naphthyl and 2-naphthyl, particularly preferably phenyl;

[0129] X are preferably identical.

[0130] MX₂, MX₃, MX₄ or ML¹L² can optionally be stabilized by unchargedligands. Possible uncharged ligands are the customary ligands ofcoordination chemistry, for example cyclic and acyclic ethers, amines,diamines, nitriles, isonitriles or phosphines. Particular preference isgiven to diethyl ether, tetrahydrofuran, 1,2-dimethoxyethane,tetramethylethylenediamine, acetonitrile or triphenylphosphine.Particularly in cases in which, for example, Ni-dialkyl compounds are tobe used, uncharged ligands have been found to be useful. The unchargedligands can also be used as solvents.

[0131] The conditions for the reaction are not critical per se; it isusual to mix the deprotonated ligand II and MX₂, MX₃, MX₄ and ML¹L² withone another in a suitable solvent such as benzene, toluene,ethylbenzene, ortho-xylene, meta-xylene or para-xylene, chlorobenzene,cyclohexane, acetonitrile, tetrahydrofuran, methylene chloride or amixture of these. The temperature can be in the range from −100° C. to+150° C., preferably from −78° C. to +100° C. It is important that thereaction is carried out in the absence of oxygen and moisture.

[0132] The molar ratio of ligand to M can be in the range from 5:1 to1:5. However, since the ligands of the formula II are more difficult toobtain than the metal compounds, molar ratios of ligand: M in the rangefrom 1:1 to 1:3 are preferred. Particular preference is given tostoichiometric amounts.

[0133] The novel complexes of the formulae I a to d can be purified bythe methods customary in organometallic chemistry, with particularpreference being given to crystallization. Filtration via filter aidssuch as Celite® is also useful.

[0134] For the polymerization, it is not necessary in all cases toisolate the complexes of the present invention. It is also possible toreact a ligand of the formula II with a suitable metal compound of theformula MX₂, MX₃, MX₄ or ML¹L² only immediately prior to thepolymerization and generate the complex in situ.

[0135] If X in the metal compound of the formula MX₂, MX₃ or MX₄ isselected from the group consisting of C₁-C₈-alkyl groups,C₃-C₁₂-cycloalkyl groups, C₇-C₁₃-aralkyl groups and C₆-C₁₄-aryl groups,the deprotonation of the ligand of the formula II can be omitted. Inthese cases, it has been found to be preferable not to isolate thecomplexes of the present invention but instead to generate them in situonly immediately prior to the polymerization.

[0136] The preparation of the ligands of the formula II a and II b isdescribed in the parallel patent applications DE-A 10107045 and DE-A10107043.-They can be obtained by reacting a deprotonated imine ornitrile having an acidic a-H atom with an electrophilic compound of theformula III

[0137] where the variables are as defined above.

[0138] It has been found that the novel complexes of the formulae I a toI d are suitable for polymerizing olefins. They are particularly usefulfor polymerizing and copolymerizing ethylene and propylene to form highmolecular weight polymers.

[0139] For the novel complexes of the formulae I a to d to becatalytically active, they have to be activated. Suitable activators areselected aluminum and boron compounds bearing electron-withdrawingradicals (e.g. trispentafluorophenylborane,trispentafluorophenylaluminum, N,N-dimethylaniliniumtetrakispentafluorophenylborate, tri-n-butylammoniumtetrakispentafluorophenylborate, N,N-dimethylaniliniumtetrakis(3,5-bisperfluoromethyl)phenylborate, tri-n-butylammoniumtetrakis(3,5-bisperfluoromethyl)phenylborate and trityliumtetrakispentafluorophenylborate). Preference is given todimethylanilinium tetrakispentafluorophenylborate, trityliumtetrakispentafluorophenylborate and trispentafluorophenylboran.

[0140] If boron or aluminum compounds are used as activators for thenovel complexes of the formulae I a to d, they are generally used in amolar ratio of from 1:10 to 10:1, based on M; they are preferably usedin a ratio of from 1:2 to 5:1 and particularly preferably instoichiometric amounts.

[0141] Another suitable class of activators are aluminoxanes.

[0142] The structure of the aluminoxanes is not known precisely. Theyare products which are obtained by careful partial hydrolysis ofaluminum alkyls (cf. DE-A 30 07 725). These products are not in the formof pure chemical compounds, but are mixtures of open-chain and cyclicstructures of the types IV a and IV b. These mixtures are presumably indynamic equilibrium.

[0143] In the formulae IV a and IV b the radicals R^(m) are each

[0144] C₁-C₁₂-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl,neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl,n-heptyl, isoheptyl, n-octyl, n-nonyl, n-decyl or n-dodecyl, preferablyC₁-C₆-alkyl such as methyl, ethyl, n-propyl, isopropyl, n-butyl,isobutyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, sec-pentyl,neopentyl, 1,2-dimethylpropyl, isoamyl, n-hexyl, isohexyl, sec-hexyl,particularly preferably methyl;

[0145] C₃-C₁₂-cycloalkyl such as cyclopropyl, cyclobutyl, cyclopentyl,cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl,cycloundecyl or cyclododecyl, preferably cyclopentyl, cyclohexyl orcycloheptyl;

[0146] C₇-C₂₀-aralkyl, preferably C₇-C₁₂-phenylalkyl such as benzyl,1-phenethyl, 2-phenethyl, 1-phenylpropyl, 2-phenylpropyl,3-phenylpropyl, 1-phenylbutyl, 2-phenylbutyl, 3-phenylbutyl or4-phenylbutyl, particularly preferably benzyl, or

[0147] C₆-C₁₄-aryl such as phenyl, 1-naphthyl, 2-naphthyl, 1-anthryl,2-anthryl, 9-anthryl, 1-phenanthryl, 2-phenanthryl, 3-phenanthryl,4-phenanthryl or 9-phenanthryl, preferably phenyl, 1-naphthyl or2-naphthyl, particularly preferably phenyl; and

[0148] n is an integer from 0 to 40, preferably from 1 to 25 andparticularly preferably from 2 to 22.

[0149] Cage-like structures for aluminoxanes are also discussed in theliterature (Y. Koide, S. G. Bott, A. R. Barron Organometallics 1996, 15,2213-26; A. R. Barron Macromol. Symp. 1995, 97, 15-25). Regardless ofthe actual structure of the aluminoxanes, they are suitable asactivators for the novel metal complexes of the formula I.

[0150] Mixtures of various aluminoxanes are particularly preferredactivators in cases when the polymerization is carried out in a solutionin a paraffin, for example n-heptane or isododecane. A particularlypreferred mixture is the COMAO available commercially from Witco GmbH,which has the formula [(CH₃)_(0.9)(iso-C₄H₉)_(0.1)AlO]_(n).

[0151] To activate the complexes of the formulae I a to d by means ofaluminoxanes, an excess of aluminoxane, based on M, is generallynecessary. Appropriate molar ratios of M:Al are in the range from 1:10to 1:10 000, preferably from 1:50 to 1:1000 and particularly preferablyfrom 1:100 to 1:500.

[0152] It is generally believed that activators for metal complexes ofthe formulae I a to d abstract a ligand L¹ or L². Instead of aluminumalkyl compounds of the formula III a or III b or the above-describedaluminum or boron compounds having electron-withdrawing radicals, theactivator can also be, for example, an olefin complex of rhodium ornickel.

[0153] Preferred nickel-(olefin)_(y)-complexes, where y=1, 2, 3 or 4,available commercially from Aldrich are Ni(C₂H₄)3,Ni(1,5-cyclooctadiene)₂ “Ni(COD)₂”, Ni(1,6-cyclodecadiene)₂ orNi(1,5,9-all-trans-cyclododecatriene)₂. Particular preference is givento Ni(COD)₂.

[0154] Particularly useful activators of this type are mixedethylene/1,3-dicarbonyl complexes of rhodium, for exampleethylenerhodium acetylacetonate Rh(acac)(CH₂═CH₂)₂, ethylenerhodiumbenzoylacetonate Rh(C₆H₅—CO—CH—CO—CH₃) (CH₂=CH₂)₂ orRh(C₆H₅—CO—CH—CO—C₆H₅)(CH₂=CH₂)₂. Rh(acac)(CH₂═CH₂)₂ is most suitable.This compound can be synthesized by the method of R. Cramer in Inorg.Synth. 1974, 15, 14.

[0155] Some of the complexes of the formula I can be activated byethylene. The ease of the activation reaction depends critically on thenature of the ligand L¹.

[0156] Depending on the synthesis conditions, the complexes of thepresent invention can be obtained as monomers or else as dimers whichare bridged via two of the substituents L². The activation does notdepend critically on whether the complexes are in monomeric or dimericform.

[0157] The chosen complex of the formula I and the activator togetherform a catalyst system.

[0158] The activity of the catalyst system of the invention can beincreased by addition of further aluminum alkyl of the formulaAl(R^(m))₃ or aluminoxanes, particularly when compounds of the formulaIV a or IV b or the abovementioned aluminum or boron compounds havingelectron-withdrawing radicals are used as activators; aluminum alkyls ofthe formula Al(R^(m))₃ or aluminoxanes can also act as molar massregulators. A further effective molar mass regulator is hydrogen. Themolar mass can be regulated particularly effectively via the reactiontemperature and the pressure. If a boron compound as described above isto be used, the addition of an aluminum alkyl of the formula Al(R^(m))₃is particularly preferred.

[0159] It has been found that the novel complexes of the formulae I a tod are suitable for polymerizing olefins. They are particularly usefulfor polymerizing and copolymerizing ethylene and propylene.

[0160] Pressure and temperature conditions during the polymerization canbe chosen within wide limits. Pressures in a range from 0.5 bar to 4000bar have been found to be useful; preference is given to from 10 to 75bar or high-pressure conditions of from 500 to 2500 bar. A suitabletemperature range has been found to be from 0 to 120° C., preferablyfrom 40 to 100° C. and particularly preferably from 50 to 85° C.

[0161] As monomers, mention may be made of the following olefins:ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-deceneand 1-undecene, with propylene and ethylene being preferred and ethylenebeing particularly preferred.

[0162] Suitable comonomers are a-olefins, for example from 0.1 to 20 mol% of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene,1-decene or 1-undecene. Further suitable comonomers are isobutene andstyrene, also internal olefins such as cyclopentene, cyclohexene,norbornene and norbornadiene.

[0163] Solvents which have been found to be suitable are toluene,ortho-xylene, meta-xylene, para-xylene and ethylbenzene and alsomixtures of these, such as diethyl ether, tetrahydrofuran,chlorobenzene, 1,3-dichlorobenzene, dichloromethane and also, underhigh-pressure conditions, supercritical ethylene.

[0164] Hydrogen has been found to be an effective chain transfer agentin polymerizations using the novel complexes of the formula I, i.e. themolecular weight of the polymers obtainable by means of the catalystsystem of the present invention can be reduced by addition of hydrogen.If sufficient hydrogen is added, waxes are obtained. The hydrogenconcentration required for this depends, inter alia, on the type ofpolymerization plant employed.

[0165] For the catalyst systems of the present invention to be able tobe used in modern polymerization processes such as suspensionprocesses., bulk polymerization processes or gas-phase processes, theyhave to be immobilized on a solid support. Otherwise, morphologyproblems with the polymer (lumps, deposits on walls, blockages in linesor heat exchangers) can occur and force shutdown of the plant. Such animmobilized catalyst system will be referred to as a catalyst.

[0166] It has been found that the catalyst systems of the presentinvention can be readily deposited on solid support materials. Suitablesupport materials are, for example, porous metal oxides of metals ofgroups 2 to 14 or mixtures thereof, also sheet silicates and zeolites.Preferred examples of metal oxides of groups 2 to 14 are SiO₂, B₂O₃,Al₂O₃, MgO, CaO and ZnO. Preferred sheet silicates are montmorillonitesand bentonites; the preferred zeolite is MCM-41.

[0167] Particularly preferred support materials are spherical silicagels and aluminosilicate gels of the formula SiO₂.a Al₂O₃, where a isgenerally from 0 to 2, preferably from 0 to 0.5. Such silica gels arecommercially available, e.g. Silica Gel SG 332, Sylopol® 948 or 952 or S2101 from W. R. Grace or ES 70X from Crosfield.

[0168] As regards the particle size of the support material, meanparticle diameters which have been found to be useful are from 1 to 300μm, preferably from 20 to 80 μn, determined by known methods such assieve methods. The pore volume of these supports is from 1.0 to 3.0ml/g, preferably from 1.6 to 2.2 ml/g and particularly preferably from1.7 to 1.9 ml/g. The BET surface area is from 200 to 750 m²/g,preferably from 250 to 400 m²/g.

[0169] To remove impurities, in particular moisture, adhering to thesupport material, the support materials can be baked before doping, withtemperatures of from 45 to 1000° C. being suitable. Temperatures of from100 to 750° C. are particularly useful for silica gels and other metaloxides. This baking can be carried out for from 0.5 to 24 hours,preferably from 1 to 12 hours. The pressure conditions depend on theprocess chosen; baking can be carried out in a fixed-bed process, astirred vessel or else in a fluidized-bed process. Baking can in generalbe carried out at atmospheric pressure. However, reduced pressures offrom 0.1 to 500 mbar are advantageous, a range from 1 to 100 mbar isparticularly advantageous and a range from 2 to 20 mbar is veryparticularly advantageous. In the case of fluidized-bed processes, onthe other hand, it is advisable to employ a slightly superatmosphericpressure in a range from 1.01 bar to 5 bar, preferably from 1.1 to 1.5bar.

[0170] Chemical treatment of the support material with an alkyl compoundsuch as an aluminum alkyl, a lithium alkyl or an aluminoxane is likewisepossible.

[0171] In the case of a suspension polymerization process, use is madeof suspension media in which the desired polymer is insoluble or solubleto only a slight extent, because otherwise deposits of product occur inthe parts of the plant in which the product is separated off from thesuspension medium and force repeated shutdowns and cleaning operations.Suitable suspension media are saturated hydrocarbons such as propane,n-butane, isobutane, n-pentane, isopentane, n-hexane, isohexane andcyclohexane, with isobutane being preferred.

[0172] Pressure and temperature conditions during the polymerization canbe chosen within wide limits. A suitable pressure range has been foundto be from 0.5 bar to 150 bar, preferably from 10 to 75 bar. A suitabletemperature range has been found to be from 0 to 120° C., preferablyfrom 40 to 100° C.

[0173] As monomers, mention may be made of the following olefins:ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-deceneand 1-undecene, with preference being given to ethylene.

[0174] Suitable comonomers are α-olefins, for example from 0.1 to 20 mol% of 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene,1-decene or 1-undecene. Further suitable comonomers are isobutene andstyrene, also internal olefins such as cyclopentene, cyclohexene,norbornene and norbornadiene.

[0175] Furthermore, hydrogen has been found to be an effective chaintransfer agent in polymerizations using the catalysts of the presentinvention, i.e. the molecular weight of the polymers obtainable by meansof the catalysts of the present invention can be reduced by addition ofhydrogen. If sufficient hydrogen is added, waxes are obtained. Thehydrogen concentration required for this depends, inter alia, on thetype of polymerization plant employed. Addition of hydrogen increasesthe activity of the catalysts of the present invention.

[0176] The catalysts of the present invention can also be used togetherwith one or more other polymerization catalysts known per se. Thus, theycan be used together with

[0177] Ziegler-Natta catalysts,

[0178] supported metallocene catalysts containing transition metals ofgroups 4 to 6 of the Periodic Table of the Elements,

[0179] catalysts based on late transition metals (WO 96/23010),

[0180] Fe or Co complexes with pyridyldiimine ligands, as are disclosedin WO 98/27124,

[0181] or chromium oxide catalysts of the Phillips type.

[0182] If a plurality of catalysts is used, it is possible to mixvarious catalysts with one another and to meter them in together or touse cosupported complexes on a common support or else to meter variouscatalysts separately into the polymerization vessel at the same point orat various points.

[0183] It has also been found that the novel complexes of the formulae Ia and I b, in particular those in which M=Ni, are particularly suitablefor the polymerization or copolymerization of 1-olefins, preferablyethylene, in emulsion polymerization processes.

[0184] Apart from other 1-olefins as comonomers, for example propene,1-butene, 1-hexene, 1-octene or 1-decene, the catalyst system of thepresent invention also enables polar comonomers to be incorporated, withfrom 0.1 to 50 mol % of comonomer being able to be used. Preference isgiven to

[0185] acrylates such as acrylic acid, methyl acrylate, ethyl acrylate,2-ethylhexyl acrylate, n-butyl acrylate or tert-butyl acrylate;

[0186] methacrylic acid, methyl methacrylate, ethyl methacrylate,n-butyl methacrylate or tert-butyl methacrylate;

[0187] vinyl carboxylates, particularly preferably vinyl acetate,

[0188] unsaturated dicarboxylic acids, particularly preferably maleicacid,

[0189] unsaturated dicarboxylic acid derivatives, particularlypreferably maleic anhydride and alkylimides of maleic acid, e.g.N-methylmaleimide.

[0190] Furthermore, it is possible to prepare terpolymers comprising atleast 2 of the abovementioned monomers together with ethylene.

[0191] The emulsion polymerization of the 1-olefins using the novelmetal complexes of the formula I can be carried out in a manner knownper se.

[0192] The order of addition of the reagents in the emulsionpolymerization is not critical. Thus, the solvent can firstly bepressurized with gaseous monomer or liquid monomer can be metered in,after which the catalyst system is added. However, the solution of thecatalyst system can also firstly be diluted with further solvent, afterwhich monomer is added.

[0193] The actual polymerization usually proceeds at a minimum pressureof 1 bar; below this pressure, the polymerization rate is too low.Preference is given to 2 bar and particular preference is given to aminimum pressure of 10 bar.

[0194] The maximum practical pressure is 4000 bar; at higher pressures,the demands made on the material of construction of the polymerizationreactor are very high and the process becomes uneconomical. Preferenceis given to 100 bar and particular preference is given to 50 bar.

[0195] The polymerization temperature can be varied within a wide range.The minimum practical temperature is 10° C., since the polymerizationrate decreases at low temperatures. Preference is given to a minimumtemperature of 40° C., particularly preferably 65° C. The temperatureshould not exceed 350° C. and is preferably not above 150° C.,particularly preferably not above 100° C.

[0196] Prior to the polymerization, the complex of the formulae I a to dis dissolved in an organic solvent or in water. The solution is stirredor shaken for a number of minutes to ensure that it is clear. Thestirring time can be, depending on the solubility of the compoundconcerned, from 1 to 100 minutes.

[0197] At the same time, any activator necessary is dissolved in asecond portion of the same solvent or else in acetone.

[0198] Suitable organic solvents are aromatic solvents such as benzene,toluene, ethylbenzene, ortho-xylene, meta-xylene and para-xylene andalso mixtures thereof. Further suitable solvents are cyclic ethers suchas tetrahydrofuran and dioxane or acyclic ethers such as diethyl ether,di-n-butyl ether, diisopropyl ether or 1,2-dimethoxyethane. Ketones suchas acetone, methyl ethyl ketone or diisobutyl ketone are also suitable,and the same applies to amides such as dimethylformamide ordimethylacetamide. It is also possible to use mixtures of these solventswith one another and mixtures of these solvents with water or alcoholssuch as methanol or ethanol.

[0199] Preference is given to acetone and water and mixtures of acetoneand water in any mixing ratio. The amount of solvent is likewise notcritical, but it has to be ensured that the complex and the activatorcan dissolve completely, otherwise a decrease in the activity has to beexpected. The dissolution process can, if desired, be accelerated byultrasonic treatment.

[0200] Any emulsifier which is optionally added can be dissolved in athird portion of the solvent or else together with the complex.

[0201] The amount of emulsifier is selected so that the mass ratio ofmonomer to emulsifier is greater than 1, preferably greater than andparticularly preferably greater than 20. The less emulsifier used, thebetter. The activity in the polymerization is significantly increased ifan emulsifier is added. This emulsifier can be nonionic or ionic innature.

[0202] Nonionic emulsifiers which can be used are, for example,ethoxylated monoalkylphenols, dialkylphenols and trialkylphenols (EOcontent: 3-50, alkyl radical: C₄-C₁₂) and ethoxylated fatty alcohols (EOcontent: 3-80; alkyl radical: C₈-C₃₆). Examples are the Lutensol® gradesfrom BASF AG or the Triton® grades from Union Carbide.

[0203] Customary anionic emulsifiers are, for example, alkali metal andammonium salts of alkyl sulfates (alkyl radical: C₈-C₁₂), of sulfuricmonoesters of ethoxylated alkanols (Eo content: 4-30, alkyl radical:C₁₂-C₁₈) and ethoxylated alkylphenols (EO content: 3-50, alkyl radical:C₄-C₁₂), of alkylsulfonic acids (alkyl radical: C₁₂-C₁₈) and ofalkylarylsulfonic acid (alkyl radical: C₉-C₁₈).

[0204] Suitable cationic emulsifiers are generally primary, secondary,tertiary or quaternary ammonium salts, alkanolammonium salts, pyridiniumsalts, imidazolinium salts, oxazolinium salts, morpholinium salts,thiazolinium salts and also salts of amine oxides, quinolinium salts,isoquinolinium salts, tropylium salts, sulfonium salts and phosphoniumsalts, in each case containing a C₆-C₁₈-alkyl, -aralkyl or heterocyclicradical. Examples which may be mentioned are dodecylammonium acetate orthe corresponding hydrochloride, the chlorides or acetates of thevarious 2-(N,N,N-trimethylammonium)ethyl esters of paraffinic acids,N-cetylpyridinium chloride, N-laurylpyridinium sulfate and alsoN-cetyl-N,N,N-trimethylammonium bromide,N-dodecyl-N,N,N-trimethylammonium bromide,N,N-distearyl-N,N-dimethylammonium chloride and also the geminisurfactant N,N′-(lauryldimethyl)ethylenediamine dibromide. Numerousfurther examples may be found in H. Stache, Tensid-Taschenbuch,Carl-Hanser-verlag, Munich, Vienna, 1981 and in McCutcheon's,Emulsifiers & Detergents, MC Publishing Company, Glen Rock, 1989.

[0205] The components, namely complex in solution, optionally thesolution of the emulsifier and optionally the solution of the activator,are subsequently introduced into the polymerization reactor.Polymerization reactors which have been found to be useful are stirredvessels and autoclaves and also tube reactors, with the tube reactorsbeing able to be configured as loop reactors.

[0206] The monomer or monomers to be polymerized is/are mixed with thepolymerization medium. As polymerization medium, it is possible to usewater or mixtures of water with the above-mentioned solvents. It shouldbe ensured that the proportion of water is at least 50% by volume, basedon the total mixture, preferably at least 90% by volume and particularlypreferably at least 95% by volume.

[0207] The solutions of the complex, if used the activator and if usedthe emulsifier are combined with the mixture of monomer and aqueouspolymerization medium. The order of addition of the various componentsis not critical per se. However, it is necessary for the components tobe combined sufficiently quickly for no crystallization of any sparinglysoluble complexes formed as intermediates to occur.

[0208] The process of the present invention gives polyolefins and olefincopolymers in high yields, i.e. the activity of the complexes of thepresent invention under the conditions of emulsion polymerization isvery high.

[0209] As polymerization process, continuous and batchwise processes aresuitable in principle. Preference is given to semicontinuous processes(semibatch processes) in which all components are mixed and then furthermonomer or monomer mixture is metered in during the polymerization.

[0210] The process of the present invention firstly gives aqueouspolymer dispersions.

[0211] The mean particle diameter of the polymer particles in thedispersions obtained according to the present invention is from 10 to1000 nm, preferably from 50 to 500 nm and particularly preferably from70 to 350 nm. The distribution of the particle diameters can be veryuniform, but does not have to be. For some applications, in particularfor those in which high solids contents (>55%) are present, broad orbimodal distributions are even preferred.

[0212] The polymers obtained by the process of the present inventionhave industrially interesting properties. In the case of polyethylene,they have a high degree of crystallinity, which can be shown by, forexample, the number of branches. Less than 100 branches, preferably lessthan 50 branches, per 1000 carbon atoms of the polymer, determined by¹H-NMR and ¹³C-NMR spectroscopy, are found.

[0213] The enthalpies of fusion of the polyethylenes obtainable by theprocess of the present invention are greater than 100 J/g, preferablygreater than 140 and particularly preferably greater than 180 J/g,measured by DSC.

[0214] The molecular weight distributions of the polyethylenesobtainable by the process of the present invention are narrow, i.e. theQ values are in the range from 1.1 to 3.5, preferably from 1.5 to 3.1.

[0215] Advantages of the dispersions obtained according to the presentinvention are firstly their low price owing to the cheap monomers andprocess and, secondly, that they are more stable to weathering than aredispersions of polybutadiene or butadiene copolymers. Compared todispersions of polymers comprising acrylates or methacrylates as mainmonomer, the lower tendency to undergo saponification is advantageous. Afurther advantage is that most olefins are volatile and unpolymerizedresidual monomers can easily be removed. A final advantage is that nomolar mass regulators such as tert-dodecyl mercaptan which are, firstly,difficult to separate off and, secondly, have an unpleasant odor have tobe added during the polymerization.

[0216] The polymer particles can be obtained as such by removal of thewater and, if necessary, the organic solvent or solvents from theaqueous dispersions obtained initially. Numerous customary methods areavailable for removal of the water and, if necessary, the organicsolvent or solvents, for example filtration, spray drying orevaporation. The polymers obtained in this way have a good morphologyand a high bulk density.

[0217] The particle sizes can be determined by light scattering methods.A review may be found in D. Distler “WäBrige Polymerdispersionen”,Wiley-VCH Verlag, 1st edition, 1999, Chapter 4.

[0218] The dispersions obtained according to the present invention canbe used advantageously in numerous applications, for example paperapplications such as paper coating or surface sizing, also paints andvarnishes, building chemicals, adhesives raw materials, molded foams,textile and leather applications, coatings on the reverse side ofcarpets, mattresses or pharmaceutical applications.

[0219] The following example illustrates the invention.

[0220] General Preliminary Remarks:

[0221] All work was carried out in the absence of air and moisture usingstandard Schlenk techniques. Apparatus and chemicals were preparedaccordingly. The polymer viscosity was determin d in accordance with ISO1628-3. The molar masses were determined by means of GPC. For the GPCmeasurements, the following conditions based on DIN 55672 were selected:solvent: 1,2,4-trichlorobenzene, flow: 1 ml/min, temperature: 140° C.,calibration: PE standards, instrument: Waters 150C. The number of methylgroups was determined by IR spectroscopy.

[0222] Synthesis of the Imine III.1:

[0223] The starting materials, viz. 4.97 g of acetophenone

[0224] (41.4 mmol) and 7.33 g of 2,6-diisopropylaniline (41.4 mmol),were placed in a 250 ml round-bottomed flask fitted with a waterseparator, dissolved in 70 ml of toluene and, after addition of 500 mgof p-toluenesulfonic acid, refluxed for 2 hours. The orange solution waswashed twice with H₂O and then once with 10% strength NaHCO₃ solutionuntil neutral. The organic phase was dried over Na₂SO₄. After thesolvent had been taken off on a rotary evaporator, traces of toluene andalso unreacted amine and ketone were taken off in a high vacuum at105-115° C. The oily imine crystallized overnight.

[0225] This method was used to prepare: imine III.1

[0226] Yield: 84.6%, empirical formula: C₂₀H₂₅N, color: yellow, m.p.:68-69° C.

[0227] 1H NMR (CDCl₃): 1.21 (12H, m, 4×CH₃), 2.16 (3H, S, CH₃), 2.83(2H, sept., CH), 7.11-8.12 (8H, m, phenyl)

[0228] 13C NMR (CDCl₃): 18.0, 22.9, 23.2, 28.2, 122.9, 123.3, 127.1,128.4, 130.3, 136.0, 139.1, 146.7, 164.7 (C═N)

[0229] IR (KBr, cm⁻¹): 3056 (w), 2958 (m), 2867 (m), 1630 (s), 1578 (s),1449 (s), 1366 (m), 1289 (s), 1243 (m), 1192 (m), 1111 (w), 1044 (w),1027 (m), 969 (w), 938 (m), 822 (m), 774 (vs), 760 (vs), 735 (s), 693(vs)

[0230] M+=279.2 m/e

[0231] Synthesis of the Ligand II.1

[0232] 0.18 ml of diisopropylamine (1.3 mmol) was placed in a baked-outSchlenk tube which had been flushed with argon, dissolved in 10 ml ofTHF (absolute) and admixed at −80° C. with n-BuLi (0.72 ml, 1.1equivalents, 2.0 M solution in pentane). After removal of the cold bath(EtOH, N₂), the resulting LDA solution was stirred for ½ h at roomtemperature.

[0233] The imine III.1 (0.36 g, 1.30 mmol) was added to the freshlyprepared LDA solution at −80° C. After removal of the cold bath, thedissolved starting material was stirred at room temperature for 2 hoursand thereby deprotonated (color change: yellowish to yellow-green).

[0234] 0.24 g of benzophenone (1.3 mmol) were subsequently added at roomtemperature and the mixture was stirred overnight.

[0235] The yellow THF solution was then poured into 100 ml of ice waterand extracted three times with 25 ml each time of diethyl ether. Thecombined organic phases were washed with H₂O, dried over Na₂SO₄ and theorganic solvents were removed on a rotary evaporator. The yellow productcrystallized over a period of 2 hours. Subsequent recrystallization fromethyl acetate/hexane gave the pure β-hydroxyimine II.1.

[0236] Ligand II.1

[0237] Yield: 72%, empirical formula: C₃₃H₃₅NO, color: whitish yellow,m.p.: 121-122° C.

[0238] 1H NMR (CDCl₃): 0.61 (6H, d, 2×CH₃), 0.82 (6H, d, 2×CH₃), 2.19(2H, sept, CH), 3.76 (2H, s, CH₂), 6.80-7.51 (19H, m, phenyl, OH)

[0239] 13C NMR (CDCl₃): 22.0, 24.5, 27.9 (CH₃, CH), 48.4 (CH₂), 78.5(C—OH), 122.9, 124.2, 126.0, 126.7, 127.0, 128.1, 128.2, 128.3, 129.5,130.0, 132.4, 136.8, 137.6, 143.6, 147.4 (phenyl), 170.4 (C═N)

[0240] IR (KBr, cm⁻¹): 3288 (m, broad), 3062 (w), 2962 (m), 2925 (w),2867 (m), 1634 (vs), 1492 (m), 1453 (vs), 1343 (m), 1227 (m), 1065 (m),1042 (s), 1015 (s), 942 (s), 917 (m), 899 (s), 805 (m), 749 (vs), 700(vs), 637 (s) M+=461.3 m/e

[0241] Polymerization:

[0242] 46 mg (0.1 mmol) of ligand II.1 and 40 mg (0.22 mmol) of(CH₃)₂Ni(TMEDA) were added to 250 ml of toluene in a 1 1 steel autoclaveand were mixed by stirring. The autoclave was subsequently pressurizedwith 40 bar of ethylene and polymerization was carried out at 70° C. for120 minutes. This gave 3.3 g of polyethylene, which corresponds to anactivity of 7.5 kg of polyethylene/mol of Ni·h.

[0243] TMEDA: Tetramethylethylenediamine.

1. A complex having one of the formulae I a to d,

where the variables are defined as follows: M is an element of groups 6to 10 of the Periodic Table of the Elements in the oxidation state +2 to+4; Nu is selected from among O, S and N—R⁷; R¹ to R⁷ are selected fromamong hydrogen, C₁-C₁₈-alkyl, substituted or unsubstituted,C₂-C₁₈-alkenyl, substituted or unsubstituted, having from one to 4isolated or conjugated double bonds; C₃-C₁₂-cycloalkyl, substituted orunsubstituted, C₇-C₁₃-aralkyl, C₆-C₁₄-aryl, unsubstituted or substitutedby one or more identical or different substituents selected from amongC₁-C₈-alkyl, substituted or unsubstituted, C₃-C₁₂-cycloalkyl,C₇-C₁₃-aralkyl, C₆-C₁₄-aryl, halogen, C₁-C₆-alkoxy, substituted orunsubstituted, C₆-C₁₄-aryloxy, SiR⁸R⁹R¹⁰ and O-SiR⁸R⁹R¹⁰; five- andsix-membered nitrogen-containing heteroaryl radicals, unsubstituted orsubstituted by one or more identical or different substituents selectedfrom among C₁-C₈-alkyl, substituted or unsubstituted, C₃-C₁₂-cycloalkyl,C₇-C13-aralkyl, C₆-C₁₄-aryl, halogen, C₁-C₆-alkoxy, C₆-C₁₄-aryloxy,SiR⁸R⁹R¹⁰ and O-SiR⁸R⁹R¹⁰; where adjacent radicals R¹ to R⁷ may bejoined to one another to form a 5- to 12-membered ring; L¹ is anuncharged, organic or inorganic ligand, L² is an organic or inorganicanionic ligand, where L¹ and L² may be joined to one another by one ormore covalent bonds, z is an integer from 1 to 3, R⁸ to R¹⁰ areidentical or different and are selected from among hydrogen,C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl and C₆-C₁₄-aryl.
 2. Acomplex as claimed in claim 1, wherein M is selected from among nickeland palladium.
 3. A complex as claimed in claim 1 or 2, wherein L¹ isselected from among phosphines (R¹¹)_(x)PH_(3−x), amines(R¹¹)_(x)NH_(3−x), ethers (R¹¹)₂O, H₂O, alcohols (R¹¹)OH, pyridine,pyridine derivatives of the formula C₅H_(5−x)(R¹¹)_(x)N, CO,C₁-C₁₂-alkylnitriles, C₆-C₁₄-arylnitriles and ethylenically unsaturateddouble bond systems, where x is an integer from 0 to 3; L² is selectedfrom among halide ions, amide ions (R¹¹)_(x−1)NH_(2−x), C₁-C₆-alkylanions, allyl anions, benzyl anions and aryl anions; the radicals R¹¹are identical or different and are selected from among hydrogen,C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl and C₆-C₁₄-aryl.
 4. Aprocess for preparing a complex as claimed in any of claims 1 to 3,which comprises firstly deprotonating a ligand of the formula II a or IIb

by means of a base and subsequently reacting the product with from 0.2to 5 equivalents of a metal compound MX₄, MX₃, ML¹L² or MX₂, where X ishalogen, C₁-C₈-alkyl, C₃-C₁₂-cycloalkyl, C₇-C₁₃-aralkyl or C₆-C₁₄-aryland where MX₂, MX₃ or MX₄ may optionally be stabilized by furtheruncharged ligands.
 5. A process for the polymerization orcopolymerization of olefins using a complex as claimed in any of claims1 to
 3. 6. A process for preparing a supported catalyst for thepolymerization or copolymerization of olefins, which comprisesdepositing one or more complexes as claimed in any of claims 1 to 3 andoptionally an activator on a solid support.
 7. A supported catalyst forthe polymerization or copolymerization of olefins which is prepared asset forth in claim
 6. 8. A process for the polymerization orcopolymerization of olefins using a supported catalyst as claimed inclaim
 7. 9. A process for the emulsion polymerization orcopolymerization of ethylene or other 1-olefins and optionally furtherolefins using a complex having one of the formulae I a to d as claimedin any of claims 1 to 3.